In a multi-ratio transmission produced in large quantities, it is already known to situate the planetary gear set of a range-change group, together with the clutch, in an area outside that of the main transmission. The planetary gear set and the clutch are here separated from the main transmission by a partition wall, where shafts and gearshift rods of the main transmission can also be situated. For the support of torques exerted, for instance, by a clutch body of the clutch, the intermediate wall must be designed, for instance, with reinforcing webs or fins, so as to be able to resist the torques that appear. For this purpose, said wall can be firmly clamped between the main transmission and the casing of the range-change group placed outside. This creates difficulties in the aluminum, as result of the necessary pressure.
Idler gears are often supported in the main part of the transmission by bearing studs anchored in the casing of the transmission. The intermediate gears of the reverse gear, in particular, require a separate support, since these (sic) are not connected with the countershafts of the transmission.
A simplified construction of the transmission contributes to the saving of material and assembly time. It is often advantageous here to combine different parts of the assemblies into one structural part, that is, accomplish several functions with only one suitably designed part.
WO 90/10806 has thus disclosed a main casing of a multi-ratio transmission in which is situated a range-change transmission. One element of the clutch is here supported over an intermediate plate of the transmission casing, said intermediate plate being clamped between the casing parts of the main transmission and the range-change transmission. But the intermediate plate shown there is not capable of assuming other functions in the transmission.